1. Field of the Invention
This invention pertains to reduced-fat peanut butter compositions. More particularly, this invention pertains to peanut butter compositions in the form of water-in-oil emulsions which comprise a continuous peanut butter oil phase and a discontinuous aqueous coagulated protein phase. The aqueous protein phase comprises an aqueous solution of a coagulable protein, a protein coagulating agent. The aqueous protein phase extends the peanut butter oil phase to provide peanut butter compositions having fewer calories and less fat than conventional peanut butter compositions. The improved peanut butter compositions may be used directly or may be incorporated into edible carriers to provide a wide variety of ingestible compositions.
2. Description of the Prior Art
Peanut butter is a cohesive, comminuted mixture of ground peanut particles suspended in liquid peanut oil. Peanut butter is prepared by roasting, blanching, and grinding shelled peanuts to form a peanut paste. During the grinding step, the cellular structure of the peanuts is ruptured releasing the peanut oil in which the pulverized peanut particles become suspended. A stabilizing agent such as a high melting point fat is generally added to the peanut paste to prevent separation of the phases. An emulsifying agent, a sweetening agent, and salt may also be added to the peanut paste.
The protein content of peanut butter is from about 26% to about 30% making peanut butter a nutritious food. The oil or fat content of peanut butter, however, is from about 48% to about 53% mitigating the nutritional value of peanut butter. Accordingly, low-fat peanut butters having the flavor and texture of conventional peanut butters are desirable.
Attempts to make low-fat peanut butter have generally focused on removing a portion of the peanut oil found in peanuts and replacing the oil with a low-fat and low-calorie filler substitute. These low-calorie peanut butter compositions have generally been unsatisfactory because the peanut oil removal step tends to also remove a portion of the flavor components from the peanut butter resulting in a peanut butter with poor taste. In addition, the low-fat filler substitutes generally do not provide the texture and consistency properties of conventional peanut butter.
U.S. Pat. No. 4,863,753, issued to Hunter et al., discloses a reduced-calorie peanut butter composition in which a portion of the peanut oil is replaced by triglycerides containing medium chain fatty acids.
U.S. Pat. No. 4,814,195, issued to Yokovama et al., discloses a reduced-calorie peanut butter composition containing from about 15% to about 40% of a low-calorie solid bulking agent such as polydextrose or microcrystalline cellulose.
U.S. Pat. No. 4,228,190, issued to Wallgren et al., discloses a margarine composition in the form of a water-in-oil emulsion which comprises a fat phase present in an amount from about 35% to about 65% and an aqueous precipitated protein phase, present in an amount from about 35% to about 65%. Wallgren et al. forms the aqueous precipitated protein phase by coagulating milk protein with rennet and the calcium already present in casein. Wallgren et al. does not teach to add a protein complexing agent.
U.S. Pat. No. 3,580,729, issued to Darragh et al., discloses a peanut spread supplemented with from about 15% to about 25% of soybean protein and from about 15% to about 25% of liquid vegetable oil.
U.S. Pat. No. 3,552,980, issued to Cooper et al., discloses a spreadable food product consisting of two discrete spreads in contact with each other. One spread is hydrophilic such as a peanut butter and the other spread is a modified sweet aqueous spread such as a jelly. The sweet aqueous spread is modified to contain in the non-aqueous portion less than 50% carbohydrates having a molecular weight of less than about 200 to prevent migration of moisture from the sweet aqueous spread to the hydrophilic spread.
U.S. Pat. No. 2,388,91, issued to Oatman, discloses a method for precipitating casein from dried skim milk which consists of mixing the dried skim milk with fresh skim milk and precipitating the casein with an acid, sour whey, or rennet.
While the above references disclose a variety of reduced-fat peanut butter compositions, none of the above compositions are entirely satisfactory. Removing peanut oil from peanut butter results in a peanut butter lacking flavor and adding low-fat filler substitutes results in a peanut butter with poor texture and consistency. Thus it would be commercially advantageous to provide a reduced-fat peanut butter composition which has the flavor and consistency of conventional peanut butter. The present invention provides such improved reduced-fat peanut butter compositions without the disadvantages characteristic of previously known products. This invention also pertains to methods for preparing these reduced-fat peanut butter compositions and the ingestible compositions in which they may be employed.